A few years ago, the clear, shallow waters of Mar Menor, a saltwater lagoon off eastern Spain that is Europe's largest, hosted a robust population of fan mussels, a meter long bivalve. A massive algal bloom in 2016 sucked up the lagoon's oxygen and killed 98% of the bivalves.

Millions of dead fish were washed onto the shore. Local residents had had enough of tourism to the lagoon. Activists started a petition to grant the rights of personhood in the 135- square-kilometer lagoon. Spain's Senate approved a bill enshrining the lagoon's new rights on September 21st.

The law doesn't consider the lagoon and its Watershed to be fully human. The ecosystems now have a legal right to exist and evolve. It has a scientific committee which will give its defenders a new voice.

There is a senior lecturer in constitutional law at the university. The new law has a lot of powerful elements.

The first environment in Europe to get such rights is the lagoon. In Bangladesh, the Ganges and every river have been granted personhood, as well as in other parts of the world. Catherine Iorns Magallanes is an environmental law expert at the Victoria University of Wellington.

The Whanganui River in New Zealand is said to be the most successful story. The river can be sued, enter contracts, and hold property like a person. The goal was to incorporate the Mori connection between people and nature into Western law. In 1994, a Mori elder wrote about the importance of the river and its people.

Julia Talbot-Jones, an expert in environmental and natural resource issues at VUW, says that the move appears to be paying off for the environment. She says that granting rights to the Whanganui River has been an important step.

Existing laws already protect species, habitats, and water quality in Mar Menor. People and institutions are not allowed to harvest or harm the fan mussel, which is found in rivers and lakes. Francisca Gimenez-Casalduero is a marine ecologist at the University of Alicante. She is sad about that failure and the state of the lagoon.

Over the next five years, Spain's environmental ministry will commit nearly 500 million to address pollution in Mar Menor. A large amount of algae was removed from the lagoon. There are illegal irrigation canals that the government is trying to destroy to stop the water from flowing into the lagoon. The new legal framework will help these efforts.

It is now possible for any citizen to file a lawsuit to protect Mar Menor. The legal guardians, made up of representatives from government and citizens who have yearslong appointments, can suggest legal and other actions on behalf of the lagoon. Ecological health will be gauged by establishing healthy ranges of oxygen and other variables. New threats will be identified and advised on restoration measures. Stakeholders will be included in a monitoring commission. Gimnez-Casalduero says that they have another tool for protection. Pollution and other issues afflicting Mar Menor can be controlled.

A backlash is possible due to the new law. The far-right Vox party called the initiative "legal nonsense" and said it would appeal to Spain's Constitutional court. It will be important to build broader support. Environmental law researcher Elizabeth Macpherson says that top-down declarations can be empty.

Property rights of farmers need to be recognized in the current legal framework. Talbot- Jones says that step is crucial. They will be involved in litigation if there is ambiguity.

Others will be watching. Groups in the United Kingdom are campaigning for the rights of the rivers. The success of the rights of nature campaign in Spain shows the other European nations what is possible.